This invention relates to a method for simultaneously producing two continuous streams of cigarettes.
U.S. Pat. No. 4,336,812 of the present applicant describes a production machine able to simultaneously produce two continuous cigarette rods starting from a single paper web, which is cut longitudinally to form two substantially identical strips. The said two strips are fed, by respective side-by-side conveyor belts driven by a common drive roller, along a forming bench for said rods by way of a loading station, in which a respective shredded tobacco filler is fed on to each strip.
One of the major functional drawbacks of the aforesaid machine derives from the use of said common drive roller, which implies identical dynamic behaviour of the two conveyor belts. This does not happen in practive, as one conveyor belt is never identical to another, with the result that when two theoretically equal belts are mounted along identical paths about a common drive roller, they advance, when in use, at speeds which especially after a certain period of operation can be different from each other.
Because of the fact that in the aforesaid machine the two strips for the two rods are produced from the same paper web, any difference in their speed of advancement can lead, if not immediately eliminated, to the tearing of at least one of said strips.